MIAMI, FL — Police departments around the country increasingly are using sophisticated technology to surveil American citizens by monitoring cellphone data, in many cases carefully hiding those activities from the public and the press.

The American Civil Liberties Union, along with The Associated Press and USA Today, have all done important work recently to shine a light in the surveillance shadows. Local news outlets, including some here in Florida, have also done valuable reporting on the use of the technology, which offers investigative benefits but also raises constitutional concerns.

It’s vital that a close look at these surveillance practices continues. Local journalists in particular have an opportunity to serve their readers by building on the work that’s been done—work that has raised serious questions about an area of high public interest, and already has had demonstrated impact.

But it’s vital, too, to understand the government secrecy that has surrounded these techniques—and how the relationships between local police and state and federal agencies, which sometimes supply the equipment, challenge public records laws. It’s going to take a multipronged media attack to get around that secrecy and learn more about what law enforcement agencies at all levels are doing.

Here in Florida, it’s not clear just what information about the technologies is covered under the state’s strong public records law. Records requests have produced a variety of responses, many of them not especially forthcoming.

But it is clear that federal law enforcement is playing a key role in maintaining a shroud of secrecy. On Tuesday, a state trial judge here dismissed an action by the ACLU to obtain police documents about use of the surveillance technology under the state public records law, in part because a local detective had been deputized by the US Marshals Service. On Thursday, emails came to light revealing that police in the same judge’s jurisdiction had sought to conceal use of the technology in court records concerning local investigations—apparently at the behest of the Marshals Service.

The emails bolster the conclusion of a recent AP article: “The Obama administration has been quietly advising local police not to disclose details about surveillance technology they are using to sweep up basic cellphone data from entire neighborhoods.”

David Cuillier, president of the Society of Professional Journalists, put it more bluntly: “The feds are completely out of control on this issue, gaming the system and corrupting it to keep their program secret.”

StingRays as “confidential sources”

The technology in question consists of devices like the StingRay, manufactured by Harris Corp., that essentially function as portable faux cell towers—allowing law enforcement officers to get detailed information about the location and use of individual phones, though not the content of communications.

Civil-liberties and privacy advocates object to the widespread use of the devices, especially without court warrants, and are seeking information about their use to spur public debate. The ACLU has filed public records requests with 37 law enforcement agencies in Florida. (Disclosure: Jonathan Peters serves on the board of the ACLU of Ohio, which had no connection to the events in Florida.)

Responses to those requests varied: state police have claimed the records are exempt under state law; in one case, a local department refused to confirm or deny the existence of such records. But the most remarkable response came from the Sarasota Police Department, which in May was poised to release to Michael Barfield, vice president of the ACLU of Florida, records concerning applications and orders related to the department’s use of surveillance devices.

However, hours before the scheduled release, the records were instead seized by the Marshals Service, which had intervened to claim the records as its own, as the Sarasota Herald-Tribune reported. The federal agency said it had deputized the Sarasota officer who created the records, and therefore they were federal property not subject to state public records law.

Scott Ponce, a Miami-based media lawyer at Holland & Knight, described the intervention as “gamesmanship,” adding, “We deal frequently with state agencies giving copies of documents to federal agencies, and incorrectly claiming that something about the transfer makes them exempt from state public records law, but I have never seen the transfer of the creator of the records.”